苝/酞菁衍生物薄膜的制备与表征

 通过真空沉积法制备了苝类和酞菁类衍生物的单、双层薄膜,并对其进行了原子力显微镜形貌表征和傅里叶变换红外光谱、紫外/可见吸收光谱和荧光光谱表征。结果显示：这些薄膜的表面光滑、平整,在450～750 nm有宽而强的吸收,虽然单层薄膜有较强的吸收,但是复合双层薄膜却表现出很强的荧光淬灭。这符合靶丸高压缩内爆对激光烧蚀均匀化的要求。     

染料敏化太阳能电池光敏剂卟啉儿茶酚的密度泛函和含时密度泛函研究

用密度泛函理论的杂化密度泛函B3LYP方法研究了太阳能电池光敏荆5,10,15.三苯基-20-(3,4-二羟基苯)卟啉(卟啉儿荼酚,TPP-cat)的几何结构、电子结构、IR和Raman特性.用自然键轨道方法分析了电荷布居和成键性质.计算结果表明,最强的IR吸收峰位于1175.81 cm-1处,最强的Raman活性位于1587.18 cm-1处.采用含时密度泛函计算了TPP-cat在水溶液中的电子吸收谱,其Soret带和Q带均指认为π→π*跃迁,在大约354 cm-1处的跃迁与一个光诱导分子内电荷转移过程有关.     

基于有机染料盐掺杂薄膜体系的能量转移及光致发光特性研究

利用稳态和时间分辨瞬态光谱研究了有机盐trans-4-［p-(N-ethyl-N-(hydroxyethyl)amino)phenylstyryl］-N-(hydroxyethyl)pyridinium iodide (ASPI)掺杂聚合物PVK(聚乙烯咔唑)薄膜体系的光致发光和能量转移特性. 在ASPI：PVK掺杂薄膜体系中,PVK的荧光强度与寿命随掺杂浓度的升高而降低,表明两者存在有效的Forster能量转移. 通过在相对低浓度的掺杂体系中加入适量高量子效率的Alq3作为能量转移过渡体,形成能量转移级 关键词： 有机染料盐 荧光光谱 荧光寿命 能量转移     

Ultrahigh-resolution laser spectroscopy of the S1B2u ← S0Ag transition of perylene

A rotationally resolved ultrahigh-resolution fluorescence excitation spectrum of the S₁ ← S₀ transition of perylene has been observed using a collimated supersonic jet technique in conjunction with a single-mode UV laser. We assigned 1568 rotational lines of the band, and accurately determined the rotational constants. The obtained value of inertial defect was positive, accordingly, the perylene molecule is considered to be planar with D_2h symmetry. We determined the geometrical structure in the S₀ state by ab initio theoretical calculation at the RHF/6-311+G(d,p) level, which yielded rotational constant values approximately identical to those obtained experimentally. Zeeman broadening of each rotational line with the external magnetic field was negligibly small, and the mixing with the triplet state was shown to be very small. This evidence indicates that intersystem crossing (ISC) in the S₁¹B_2u state is very slow. The rate of internal conversion (IC) is also inferred to be small because the fluorescence quantum yield is high. The rotational constants of the S₁¹B_2u state were very similar to those of the S₀¹A_g state. The slow internal conversion (IC) at the S₁ zero-vibrational level is attributed to a small structural change upon electronic transition.     

Spectral‐Luminescence and Generation Properties of 1‐Aza‐2‐Methyl‐6‐Aminopyrene and of Its Protolytic Forms

Spectral manifestations of protolytic forms of 1aza2methyl6aminopyrene in ethanol and aqueous solutions are investigated. The ionization constants of the protolytic forms are determined. The generation properties and photostability of a neutral molecule and a cation in excitation by an excimer XeCl laser are studied.     

溶液自由基ESR谱的计算机模拟

根据溶液自由基电子自旋共振(ESR)原理,用高级BASIC语言编写了溶液自由基谱的模拟程序。自由基的ESR能级用一级近似求解,谱线的线型采用洛仑兹和高斯型的混合线型函数,程序规定体系中核自旋量子数可从1/2到7/2,不等性核的数目最多可达10组,每组中等性核的数目原则上不受限制。通过二萘嵌苯阳离子自由基和硝基苯负离子自由基谱模拟二个例子加以说明,模拟结果是满意的。     

Development of temporal spectroscopic properties for Xerogel matrices doped with Rhodamine 6G dye

The solid host of a laser dye modifies its spectroscopic properties with respect to its liquid host. During the Sol-Gel process the dye molecules suffer from changing their environment. Two parameters affect this matter, the change in the concentration due to the evaporation of the solvent (drying) and the caging of dye molecules inside the pores or attachment to the silica network. Rhodamine 6G absorption and fluorescence spectra with different concentrations, during Sol-Gel time processing, have been studied. Both, absorption and fluorescence spectra of the dye in the solid host, for different concentrations, show a blue-shift relative to its liquid phase.     

The collagen type I segment long spacing (SLS) and fibrillar forms: Formation by ATP and sulphonated diazo dyes

The collagen type I segment long spacing (SLS) crystallite is a well-ordered rod-like molecular aggregate, ∼300 nm in length, which is produced in vitro under mildly acidic conditions (pH 2.5–3.5) in the presence of 1 mM ATP. The formation of the SLS crystallite amplifies the inherent linear structural features of individual collagen heterotrimers, due to the punctate linear distribution and summation of the bulkier amino acid side chains along the length of individual collagen heterotrimers. This can be correlated structurally with the 67 nm D-banded collagen fibril that is found in vivo, and formed in vitro. Although first described many years ago, the range of conditions required for ATP-induced SLS crystallite formation from acid-soluble collagen have not been explored extensively. Consequently, we have addressed biochemical parameters such as the ATP concentration, pH, speed of formation and stability so as to provide a more complete structural understanding of the SLS crystallite. Treatment of collagen type I with 1 mM ATP at neutral and higher pH (6.0–9.0) also induced the formation of D-banded fibrils. Contrary to previous studies, we have shown that the polysulphonated diazo dyes Direct red (Sirius red) and Evans blue, but not Congo red and Methyl blue, can also induce the formation of SLS-like aggregates of collagen, but under markedly different ionic conditions to those employed in the presence of ATP. Specifically, pre-formed D-banded collagen fibrils, prepared in a higher than the usual physiological NaCl concentration (e.g. 500 mM NaCl, 20 mM Tris-HCl pH7.4 or x3 PBS), readily form SLS aggregates when treated with 0.1 mM Direct red and Evans blue, but this did not occur at lower NaCl concentrations. These new data are discussed in relation to the anion (Cl⁻) and polyanion (phosphate and sulphonate) binding by the collagen heterotrimer and their likely role in collagen fibrillogenesis and SLS formation.     

Ultrasonically induced ZnO–biosilica nanocomposite for degradation of a textile dye in aqueous phase

In the present study, a porous clay-like support with unique characteristics was used for the synthesis and immobilization of ZnO nanostructures to be used as sonocatalyst for the sonocatalytic decolorization of methylene blue (MB) dye in the aqueous phase. As a result, the sonocatalytic activity of ZnO–biosilica nanocomposite (77.8%) was higher than that of pure ZnO nanostructures (53.6%). Increasing the initial pH from 3 to 10 led to increasing the color removal from 41.8% to 88.2%, respectively. Increasing the sonocatalyst dosage from 0.5 to 2.5 g/L resulted in increasing the color removal, while further increase up to 3 g/L caused an obvious drop in the color removal. The sonocatalysis of MB dye over ZnO–biosilica nanocomposite was temperature-dependent. The presence of methanol produced the most adverse effect on the sonocatalysis of MB dye. The addition of chloride and carbonate ions had a negligible effect on the sonocatalysis, while the addition of persulfate ion led to increasing the color removal from 77.8% to 99.4% during 90 min. The reusability test exhibited a 15% drop in the color removal (%) within three consecutive experimental runs. A mineralization efficiency of 63.2% was obtained within 4 h.     

偶氮基染料掺杂薄膜的双光子图象存储

研究了偶氮基染料掺杂薄膜ＭＯ－ＰＶＡ和ＥＯ－ＰＶＡ的双光子存储特性。在对薄膜用Ａｒ＾＋激光作预激发下实现了Ｈｅ－Ｎｅ激光的红光存储。获得了实时和短时存储照片。光电记录存储曲线，分析了双光四能级系统的存储机制。实现确定了最佳预激发功率约为０．２８Ｗ／ｃｍ＾２，最小Ｈｅ－Ｎｅ光可存储功率密度低于０．２Ｗ／ｃｍ＾２。